Download 06-Cranial Cavity-IINew.part 22008-10

Dr. Vohra
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Dural Venous Sinuses
Dr. Vohra
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INTRODUCTION
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Dr. Vohra
The venous sinuses of the
cranial cavity are bloodfilled spaces situated
between the layers of the
dura mater.
They are lined by
endothelium.
Their walls are thick and
composed of fibrous tissue;
they have no muscular
tissue.
The sinuses have no valves.
They receive tributaries
from the brain, the diploe of
the skull, the orbit, and the
internal ear.
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Dural Venous Sinuses
Superior Sagittal Sinus
Inferior Sagittal Sinus
Straight Sinus
Transverse Sinuses
Sigmoid Sinuses
Occipital Sinus
Cavernous Sinus
Superior & Inf. Petrosal Sinuses
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SUPERIOR SAGITTAL SINUS
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Dr. Vohra
The superior sagittal
sinus occupies the upper
fixed border of the falx
cerebri.
It begins in front at the
Crista Gelli
It runs backward,
grooving the vault of the
skull, and at the internal
occipital protuberance it
deviates to one or the
other side (usually the
right) and becomes
continuous with the
corresponding transverse
sinus.
Numerous arachnoid villi
and granulations project
into it.
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SUPERIOR SAGITTAL SINUS
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Dr. Vohra
The superior
sagittal sinus
receives in its
course the
superior cerebral
veins
At the internal
occipital
protuberance it is
dilated to form the
confluence of the
sinuses
Here, the superior
sagittal sinus
usually becomes
continuous with
the right transverse
sinus; it is
connected to the
opposite transverse
sinus and receives
the occipital sinus
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INFERIOR SAGITTAL SINUS
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The inferior sagittal
sinus occupies the
free lower margin of
the falx cerebri.
It runs backward and
joins the great
cerebral vein at the
free margin of the
tentorium cerebelli to
form the straight
sinus.
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STRAIGHT SINUS
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Dr. Vohra
The straight sinus
occupies the line of
junction of the falx
cerebri with the
tentorium cerebelli.
It is formed by the union
of the inferior sagittal
sinus with the great
cerebral vein.
It ends by turning to the
left (sometimes to the
right) to form the
transverse sinus.b
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TRANSVERSE SINUSES
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The transverse sinuses are
paired structures and
begin at the internal
occipital protuberance.
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Each sinus occupies the
attached margin of the
tentorium cerebelli,
grooving the occipital
bone and the
posteroinferior angle of
the parietal bone.
They receive:
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Dr. Vohra
The right sinus is
usually continuous with
the superior sagittal
sinus.
The left sinus is
continuous with the
straight sinus.
Superior petrosal sinuses,
They end by turning
downward as the sigmoid
sinuses.
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SIGMOID SINUSES
Dr. Vohra
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The sigmoid
sinuses are a
direct
continuation of
the transverse
sinuses.
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The sinus then
turns downward
through the
jugular foramen
to become
internal jugular
vein.
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OCCIPITAL SINUS
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Dr. Vohra
The occipital sinus
is a small sinus
occupying the
attached margin of
the falx cerebelli.
It commences near
the foramen
magnum, where it
communicates with
the vertebral veins
and drains
superiorly into the
confluence of
sinuses.
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CAVERNOUS SINUSES
The internal carotid artery,
surrounded by its
sympathetic nerve plexus,
runs forward through the
sinus.
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The abducent nerve also
passes through the sinus.
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The internal carotid artery
and the nerves are separated
from the blood by an
endothelial covering.
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The third and fourth cranial
nerves, and the ophthalmic
and maxillary divisions of the
trigeminal nerve run forward
in the lateral wall of the
sinus.
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They lie between the
endothelial lining and the
• The cavernous
dura sinuses
mater. are situated in
the middle cranial fossa on each side of
the body of the sphenoid bone.
• Each sinus extends from the superior
orbital fissure in front to the apex of the
petrous part of the temporal bone behind.
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Dr. Vohra
SUPERIOR AND INFERIOR PETROSAL SINUSES
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Dr. Vohra
The superior and
inferior petrosal
sinuses are small
sinuses situated on the
superior and inferior
borders of the petrous
part of the temporal
bone on each side.
Each superior sinus
drains the cavernous
sinus into the
transverse sinus.
Each inferior sinus
drains the cavernous
sinus into the internal
jugular vein.
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Dr. Vohra
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